Hainan 1
Winter is fine, and the air ranks best among the four seasons. Pm2.5 in Sanya is around 20 for a long time. Disadvantages: it is hot in summer, and the living time in a year is only 3-5 months.
2. Guilin
Guilin is located in the north of Guangxi, with many mountains and rivers, and in the northwest of China. It is a world-famous scenic spot. The environment is protected by the government, and the government's tourism finance is sustainable, which can ensure the environment to be clean continuously. The air (pm2.5 is 20-50 in summer and 60- 150 in winter) and water sources are clean, and there are many longevity towns around. The city has a long history, profound cultural heritage, many scenic spots and many official activities on holidays, so you can feel the breath of life.
3. North Sea
As far as the climate is concerned, Beihai is very suitable in winter. Because it's not cold. But summer is not suitable, not only hot, but also long. So it is more appropriate to go to the north in summer.